The present invention is directed to toy construction sets of the general type comprising a plurality of linear structural elements and multi-position connector hubs. The hubs and structural elements can be joined in a variety of configurations, to assemble a wide variety of structures. An original form of such construction toy utilized wooden dowel rods as the linear structural elements, and the connector hubs were formed of circular wooden blocks with a plurality of radially directed sockets for the reception of the dowel rods. The inherently high cost and considerable bulk of the component parts of such a construction set were notable disadvantages.
It has been proposed in the past to form the hub connector and structural elements of plastic materials, utilizing plastic tubes as the structural elements, with hub connectors of molded plastic material. Examples of such prior proposals are reflected in the Ogsbury et al. U.S. Pat. No. 3,648,404 and the Rayment U.S. Pat. No. 4,078,328. The present invention is directed to an improvement in the type of construction presented by the beforementioned Ogsbury et al. and Rayment patents.
One of the objectives of the present invention is to provide a novel and improved molded plastic hub connector element, which is light in weight, utilizes a minimum amount of plastic material and is suitable for mass production at exceptionally low cost. The connector device of the invention is specifically designed for, although not necessarily limited to, utilizing widely available, common plastic straws, or the stock from which such straws are manufactured, as the tubular structural elements of the construction toy. The arrangement is such that large numbers of connectors may be made available at extremely low cost, enabling large and complicated constructions to be fabricated with a low cost toy set incorporating the device of the invention. By utilizing plastic straws or similar tubular plastic stock for the structural elements, the elements may be easily cut to custom lengths with a pair of household scissors, so that construction projects are not inhibited in any way by the initial selection of linear structural elements.
Pursuant to the invention, an improved injection molded plastic connector element is provided, which includes a relatively large number of connecting lugs, disposed radially about a central axis. The individual lugs, of generally circular cross sectional configuration, for reception inside the end portion of a plastic tube, are formed with a longitudinally extending slot recess which, in effect, divides the lugs into opposed, spaced-apart complimentary lug portions. The outer portion of each lug is somewhat enlarged in its effective diameter, to a size greater than the internal diameter of the tubular elements. When the tubular elements are applied over the lug, the outer portions thereof are elastically deflected towards each other to provide a snug friction fit. The lugs are slightly tapered, and the base portion of the lugs are also of a diameter slightly greater than that of the tubular element such that, when the tubular element is fully inserted over the lug, it is snugly received over the base portion, as well as the elastically deflected outer end portion.
To advantage, a thin compression post is interposed between the two spaced-apart lug portions, midway between the ends of the lug. This enables the lugs to be of relatively substantial length in relation to diameter, while at the same time minimizing plastic usage requirements by permitting a relatively thin cross section in the complimentary pairs of lug portions.
An advantageous form of the new connector hub incorporates a central cylindrical hub, adapted to receive a tubular structural element. A thin-walled web extends outwardly from the cylindrical hub and joins with a hub flange. Advantageously, the hub flange is of polygon form, with flat sides equal to the number of lugs.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of a preferred embodiment and to the drawings.